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Mostly Harmless
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Discussion Starter #1
Has anybody modified their airbox yet? I've heard conflicting stories about how holes cut in it add horsepower. Daryl Rath says a 2x3" hole adds 3 hp. eSuperbikeshop is trying to sell a billet plate for the airbox for $100, etc.

Rob
 

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That plate cost 100 clams? LOL What are they smokin??

No, I havent done anything yet. Ive had a UNI-filter on order since the day I bought my machine. (late december) Im about a belly button lints away from cancelling the UNI and getting the K&N,
 

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Hi guys,

I started on this re-jetting thing about two weeks ago, and here's what I ended up with...

1. W/B slip on with 6 discs.
2. 157.5 main jet
3. Stock needle in the 3rd (stock) slot from top
4. Stock air box, no holes drilled, etc., with the snorkel removed, and a fitting attached to the air box snorkel mount with an outerwears filter added to control dust/sand intake,,,very simple, only cost a few bucks in small parts, plus it can be returned to stock in a few minutes (I'll post a photo of how I did it later this weekend).
5. K&N filter #33-2003 in the stock air box, with the factory foam pre-filter installed.
6. Air mixture screw out to about 3 1/2 turns.
7. stock 14-37 gears, with a 38 tooth rear enroute...
8. Stock tire on hard dirt, Geckos in the dunes...


I live at sea level in SO Cal, and Ride alot a Glamis Dunes...our temps lately have been in the 65-80 deg. range...

With this set up, the quad will now lift the front wheels in 1st-3rd, without any effort or intention. It would not do that before...It will easily loft the front end from one whoop to the next at quite a good pace. I have not done any measured time/speed tests, but all who have ridden the bike from stock to the current settings say it is much faster.

I think i'm going to wait before I spend $100.00 on a jet kit. I have all the jets they offer anyway...and if anything, it might need a new needle. I want to see how everyone who buys these kits works out first...

Good luck to all...

JJ
 

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Mostly Harmless
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Discussion Starter #5
JJ:

What were the stock settings for the needle and air-fuel screw? I'm trying to convert your settings to what would be the equivelent for 4000-4500' elevation.

I like your airbox idea... I may try that myself.

Rob
 

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Rob,

The stock setting on my needle was the 3rd slot from the top. The stock air screw was set at about 3 1/2 turns out...So I basically left it stock. I did turn it in to aobut 2 1/2 turns, but it did not idle well, so I gradually backed it out to about the 3 1/2 setting.

I would think for your altitude you would be good with a 155 main jet, or maybe a 152.5....I am going to work now to "borrow" my department's digital camera, and I will post the photos and various part numbers for the parts I used to rig up the Outerwear on the stock snorkel mount. I have to admit, it is pretty trick, and fits well under the frame, next to the rear shock. Maybe I should market the parts for $50.00, which will undersell the other vendors, and make a big $38.00 profit!!!

In reality, when you think about the big picture, this quad is sucking air in through a rather small 1 1/4" hole. I see a great benefit in adding more air to the mix, but for now, I feel this setup will work well...is very cheap, and does allow you to return the set-up to stock in a matter of moments.

I may experiment with it some more after this weekend at Glamis...I'll keep you posted...

JJ
 

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Hey I dumped the whole airbox thing and went with a K&N and outer wear cover. I'm running a 175 main jet.
 

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Has anybody got that airforce jet airbox kit thing yet from esuperbikes and installed it? Just wondering how good and or easy it is to install. Would a lame brain be able to install it and the quad still run. No I'm just kidding not too much of a lame brain but don't know too much about motors. Wondering if anybody that has it thinks it was worth it. Thanks...



-Chris
 

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You can get a 6 pack of Uni-vents from Parts Unlimited. 1" each and only $9.95.
 

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you can also get the uni vents from Rocky Mountain Atv for 6.99. www.rockymountainatv.com
 

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when you go with the 175 jet and the increased air flow, are you changing any other parts or settings in the carb? also are you getting good results thru the whole rpm range?
P.S. are you using a mikuni jet or dyno jet?
I guess what i'm asking is did you install the dyno jet kit or just change your main jet. Dyno jet kit gives you a new needle along with different size mains. I don't know how effective their needle is compared to stock. i would guess it must have some advantage.
 

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CMC, I have a reputable shop tuning it and they may have added a shim to the needle. I know they drilled out some cap some they could adjust the low end. The 175 M jet was on the lean side too. It runs very crisp through all of the RPMs.
 

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god bless you guys who ride where its dry! you can get away with airboxmods. i went on a nice sloppy trail ride today(mud, creak crossings, some residual snow, etc.) and my stock airbox took on some water. i actually found drops of water between my K&N airfilter and the carb. nothing that seemed to do any real damage but i did get some sputtering and a rough idle at times(thats what made me lok into it). i considered some holes in the box and a larger mj but all bets are off now. have fun on the dunes gentlemen!!!!!!!!!

ps i dont really live in philly(philadelphia) i'm out in the rural suburbs
 

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I wonder..these air box mods..say the ones that jigi5150 did..would you get any performance from them..with the stock exhaust?? DOnt have the cash for the 399+tax cdn WB pipe...
 

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Scott the hmf pipe is just over 200 bucs and trust me you will love it!
you need to think of the motor as an airpump - the faster air goes in the faster it needs to come out. i'm not positive but i'd say if you did moderate to major intake work without any exhaust work you'd be cramming you engine. you could maybe get away with some minor intake work. i could be wrong but how it was always explained to me you really need both to feel the true gains. good luck!
 

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Yeah, thats what i figured. Actually the HMF would be a LITTLE bit more for me, living up here in CDN!

OH well..all in time i guess!
 

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Hi all,

I just plain gave up on the air box mod thing for now, and am running a slip on K&N filter and a Dynojet stage III jet kit. The motor pulls super hard from bottom to top, and yes, it does easily hit the rev limiter. I added a tach so I can learn to shift the thing right, just at 8000 rpm, where the power starts dropping off. According to Dynojet, this configuration is making about 43.5 hp at 8000 rpm, and I believe those numbers compared to how it ran stock. The staff at D/J told me that pretty much all of the 5 different Predators they tested during development all had their rev limiters kick in about 8800 +/- rpm. Mine seems to hit more like 8500.

I am runnig a DJ 180 main jet, and the DJ needle in the 2nd clip from the top. I am convinced that Polaris has set a way too early rev limiter kick in. I'm sure they did not want some over eager first year buyer to blow a motor and make a bad impression on the new machine (I guess the cracked heads will be enough anyway). I am waiting for someone to make a new CDI with a higher limiter...about 9500 rpm. The motor is supposed to be good for at least 10,000. I just want a little over-rev capability without the ignition retarding and popping...

I just got an e-mail back from Yoshimura, and they will have their complete exhaust system out in about a month. When they do one, you can be sure it will not have too large or small sized pipes, and will probably not need to be adjusted for peak performance.

I have some photos posted in my gallery page now...

Good luck to all,

JJ
 

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After going through about 100 ads in the new atv sport mag on line i found only one with predator stuff it has a new k&n air kit you can check it out at www.hotseatperformance.com

Dustin
 

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Hi all,

After so many hours of testing, so many times of re-jetting my carb, and so many hours of frustration, I have finally settled on a jetting combo that is working really well for me. For everyone's reference, I live and ride at sea level and up to about 1500' in the warm So Cal climes. I ride mostly desert and dunes. My current set-up is with the Dynojet jet kit stage III setting. I run a K&N RU-1770 slip-on filter with outerwear, a 175 DJ main jet, a #50 Mikuni Pilot jet, the mixture screw set at about 3 1/2 turns out, float level stock (+/- 7mm), and the DJ needle on the 2nd clip down from the top. I am currently running the W/B slip-on with all 8 discs and the quiet core insert at the end. The motor just plain screams with this setting. All the way up to 8500 rpm, when yes, I still get some popping. But I have firmly established that the popping is my factory CDI box, which causes a soft retard at about 8500, then full interrupt at 8800-8900. I just learned to shift at about 8000 rpm, and it runs great this way.

There are several companies that are working on new CDI boxes for the Preadator. One from Australia looks REALLY good, and will be about $350.00 +/-when ready. It has 10 different programable power curves, and a fully adjustable rev limiter. When this thing is ready, I will be one of the first in line...

Anyway, I hope this info may help some of you. I can now finally start enjoying the ride on my Predator. Oh, I also tried some new paddles, I got rid of the Gecko's and put on some 20x10x10 8 paddle Skat Trak Haulers. The difference is like day and night...I will never again run another type of paddle. This tire hooks up so well in the dunes it is unbelievable.

Good luck to you all...

JJ
 
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